[Amps] SB-220 Submerged

[Paul Whatton]

A note to add to this. Oven baking will melt the wax in tuned circuit 
adjustable cores. So don't subject the  rig to any mechanical shocks 
before you melt some wax into the cores,.

73 Paul G4DCV

Paul Whatton wrote:

>Hi Bill
>
>An amateur friend of mine has a business hiring out PMR radios. As you 
>can imagine they sometimes come back from hire in a terrible mess having 
>been dropped into everything you might imagine, the least of which is 
>dirty water. His solution is to drop them into an industrial ultrasonic 
>cleaning bath and then, as Gary suggested, oven bake them dry. Over the 
>years he has "subjected" hundreds of radios to this treatment and, 
>without fail, if it is done carefully, they work fine afterwards. The 
>ultrasonic cleaning bath is filled with tap water and a splash of some 
>commercial additive is added. I can find out what it is if you want.
>
>One day he suggested I might want to clean my transceivers by dropping 
>them in the bath. I was very reluctant but, what the hell, I trusted 
>this old friend. I did remove the mains transformers for reasons which 
>will become clear but otherwise I dropped whole rigs in the bath and 
>then oven dried them. Bingo! Not only did these radios work but they 
>worked better because the ultrasonic cleaner had got to all the contact 
>surfaces in the plugs, relays etc. The front panels sparkle like they 
>are new.
>
>The only reason I removed the mains transformers was drying time. When 
>water gets inside the windings it is difficult to dry out.
>
>What have I learnt from this? Water itself, even tap water, isn't a 
>problem provided that the radio is FULLY dried out. Dirty water, the 
>kind you have experienced is a problem because the impurities make it 
>conductive. Even if it is dried out you may experience problems from 
>conductive deposits and/or corrosion.
>
>What to do? In my opinion you should wash the SB-220 very thoroughy. I 
>think that means taking it out into the yard and very thoroughly hosing 
>it down. There is nothing to loose by doing this, it already has dirty 
>water in it. If you can find someone with a big enough industrial 
>ultrasonic cleaner then put the whole amp in it. Then dry it. And then 
>dry it again. It will take hours and hours., days and days. By all means 
>oven bake it or use the hot Sun. Total drying is vital. Last week I 
>dropped a friend's 2m mast-head preamp which was badly corroded and, he 
>thought, a write off, into the ultrasonic cleaner for 20 minutes. After 
>3 hours oven baking there was still sufficient moisture inside the tuned 
>circuits to de-tune it. After a week in the hot Sun in my shed it worked 
>perfectly. Thorough drying is crucial.
>
>Good luck! With patience I am sure you can save the amp.
>
>Paul G4DCV
>
>Bill Smith wrote:
>
>Other than the obvious "dry it out" what should a guy
>do to get a SB-220 back on after having been submerged
>in a basement for over a week?
>
>A friend of mine was away when a very bad storm
>flooded his basement.  The water flowed up the stairs
>and out the front door!!  So much for living at the
>bottom of the hill and having no check valve on his
>sump pump connection to the city sewer!!  Against city
>rules many people had connected their sump pumps to
>the city sewer.  That in turn over loaded the system
>as well as the water coming down the street filled a
>lot of basements.
>73,
>Bill
>
>Bill Smith KO4NR
>
>
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